Ink jet recording method is a printing method which conducts printing by flying small droplets of an ink composition and attaching the same to a recording medium such as papers. This ink jet recording method has the characteristic that high resolution and high definition image can be printed at high speed. In general, an ink composition used in an ink jet recording method comprises an aqueous solvent as a main component, and further contains a coloring component and a wetting agent such as glycerin for the purpose of preventing clogging.
On the other hand, where printing is conducted on recording media such as papers and clothes in which an aqueous ink composition is hard to penetrate, or materials such as metals and plastics, in which an aqueous ink composition does not penetrate, such as plates or films produced from phenol, melamine, vinyl chloride, acryl or polycarbonate, an ink composition is required to contain a component that a coloring material can stably be fixed to a recording medium.
To such a demand, a light curing ink jet ink comprising a coloring material, a light curing agent (racially polymerizable compound) and (photoradical) polymerization initiator is disclosed (for example, see Patent Document 1). It is described that this ink can prevent ink from bleeding into a recording medium, and can improve image quality.
Furthermore, to attempt improvement of film strength, chemical resistance, dispersion stability and the like, a light curing ink jet recording ink composition containing a coloring material, a urethane oligomer, a monomer having trifunctional or more reactive group, and an aqueous solvent is developed (see Patent Document 2).
Moreover, for the purpose of preventing separation of a pigment as a coloring material, improving scratch resistance and printing reliability, preventing bleeding after printing and enhancing drying properties of an ink, an ink jet recording ink comprising two components of an ink composition containing a coloring material, and a reaction liquid containing a polymerization initiator, and an ink jet recording method which prints on a recording medium using those two components are disclosed (for example, see Patent Document 3).
An ink jet recording ink comprising such two components is that a photopolymerization initiator and a light curing resin is contained in either of the ink composition or the reaction liquid. Thus, by separating into two components of the ink composition and the reaction liquid, dark reaction is suppressed, making it possible to store the ink composition and the reaction liquid over a long period of time and to obtain prints having excellent light resistance and heat resistance.
Patent Document 1: U.S. Pat. No. 5,623,001
Patent Document 2: JP-A-2000-336295
Patent Document 3: JP-A-8-218018